Page speed optimization has been Clint’s my jam for a quite a few years. As a matter of fact, he started one of the first page speed optimization services and have optimized well over 1000 websites at this point. One thing that he always did when possible was to convert PNG images to JPG, frankly, because they load a lot faster. However, he never tested the idea that a JPG vs PNG could possibly be a ranking factor beyond the load time. This test will allow us to answer that question.
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Transcription Below
And if you have any questions on the test I have the questions thing open right next to me so I'll see them pop up. Test 412 is PNG versus JPEG. I've been doing page speed optimization for quite some time and we always, as a standard practice, converted PNGs to JPEGs because typically PNGs are bigger than JPEG files and you can optimize them a little bit cleaner.
So, the natural progression is should I have one versus the other? Does that help for SEO? We did this test and Hunter set it up with nine pages with the PNG and then he flipped it around with only one page with the PNG. You can see the file sizes right here. This is significant because the results show us that the PNG ranked higher than the ones with the JPEG.
So, the PNG beat out the JPEGs essentially. I want to point out, I believe, that it's a file size. Eventhough it's minute, when you're thinking about it 36 kilobytes from 71 kilobytes it's not really that much different but there's no other factors on the pages are slowing the page down or making it faster. There's no content or etc so those are the only two things that are affecting it.
While we didn't prove – I don't say without a shadow of the doubt that PNG ~ PNGs, I'm thinking what we proved is your image file size is it plays off the page speed factor and because that PNGs were loading faster than the JPEGs we got an increased ranking from the JPEGs. I think that, at the end of the day, is really you need to find the right tools to optimize your images better.
My recommendation of choice for WordPress is Smush Pro. Otherwise, a free version of Smush is okay to handle the job and if you want to go really crazy you can do something like the WP Offload and send your stuff to Amazon after it's run the Smush Pro, the ~, the CDNs and squeeze as much time as you can. Just be careful with that.
If your pages are faster than your competitions page speed is no longer an issue for you SEO-wise. Maybe user-wise but not SEO-wise so don't go get lost chasing the rabbit down the rabbit hole with page speed. Google says three seconds or faster is their optimal for mobile. As long as you're doing that you're okay.